1. Field of the Invention
This invention relates to securing devices for retaining items in position between two counter members, an example of which would be the retention of printed circuit boards in an elongated slot within a computing equipment rack.
2. Discussion of Prior Art
Devices such as printed circuit boards (PCB's) need to be held rigidly in place if they are to function properly. Any severe movements can cause connections to the board to be broken which will result in the board, and any systems that depend on it, to either function incorrectly or cease their operation entirely. When such boards are used in environments which are hostile to their prolonged operation, for example in applications which involve sudden movements and accelerations, it is necessary to take measures to ensure that the boards are fixed firmly relative to the surrounding structure. A common method of fixing such boards in place involves the use of wedgelock devices.
A wedgelock securing device is used to secure equipment such as printed circuit boards in racks which comprise parallel counter members. Such securing devices comprise a centre wedge having sloped surfaces at its opposite ends and two end wedges each having one sloped surface that abuts one of the centre wedges sloped surfaces. The centre wedge is usually adapted so that it may be fasten to a printed circuit board.
A screw extends lengthwise through the centre wedge and connects together the two end wedges. The end wedge remote from the screw head has a threaded bore engaged by the screw such that a clockwise rotation of the screw draws the two end wedges towards each other. As the sloped surfaces of the two end wedges bear upon the sloped surfaces of the centre wedge the end wedges are caused to deflect transversely. This increases the effective width of the wedgelock assembly. As this effective width increases to that of the retaining channel, the wedgelock fastens itself in the slot. Continued clockwise rotation of the screw will tighten the device further. The wedgelock can be released by rotating the screw in an anti-clockwise direction, thereby causing the two end wedges to move apart longitudinally and hence reduce the assembly's effective width. This in turn releases the clamping force of the wedgelock assembly within the slot thereby allowing the PCB to be removed from the rack.
It is also known to provide end connectors that secure PCB's to fixed members for increased rigidity. Such connectors comprise two inter-connecting sections which are joined by a screw. One of these sections is attached firmly to the PCB and includes a bore in which the screw is located. The other section is permanently rigidly attached to a structural element so that the PCB is held firmly in place. This permanently fixed section includes a threaded bore that engages the connecting screw. When the two sections are aligned with each other the screw may be rotated clockwise causing the two sections to be drawn together by the action of the screw head bearing upon the section that is connected to the circuit board. As the screw is rotated clockwise the two sections close together and are eventually held rigidly in place to the structural element. These end connectors allow for increased rigidity which is imperative if the PCB is to remain in place and continue to function as intended.
Certain conditions have been known that require both of the two securing methods described above, namely the wedgelock device and the printed circuit board end connector, to be used contemporaneously to secure a single PCB. Such configurations are more difficult to assemble and hence fewer PCB's may be fixed in place in a given period than if only one of the described methods were to be used. This increased installation time is a result of the fact that a PCB, which is to be fixed in place using an end connector, must be fully secured to the connector before any wedgelock devices an be installed. The present invention offers a solution to the problems associated with performing multiple assembly operations involving wedgelock devices and end connectors for printed circuit board installations.